Come out again as engineers point to join (8)
I believe the answer is:
reemerge
'come out again' is the definition.
('emerge' can be a synonym for 'come out' so perhaps 'reemerge' is OK for 'come out again')
'engineers point to join' is the wordplay.
'engineers' becomes 're' (Royal Engineers).
'point' becomes 'E' (compass point).
'to join' becomes 'merge' (I've seen this before).
're'+'e'+'merge'='REEMERGE'
'as' is the link.
(Other definitions for reemerge that I've seen before include "Again become known" , "appear again" , "Come out again" , "Become visible again" .)